Cell Genesys Reports Positive Results From Phase 2 Trial of GVAX(R) Vaccine for Leukemia in Chronic Myelogenous Leukemia
Cell Genesys Reports Positive Results From Phase 2 Trial of GVAX(R) Vaccine for Leukemia in Chronic Myelogenous Leukemia
Vaccine Reduces Molecular Evidence of Persistent Leukemia After Long-Term
Gleevec(R) Therapy
ATLANTA, Dec. 12 /PRNewswire-FirstCall/ -- Cell Genesys, Inc.
(Nasdaq: CEGE) today reported encouraging clinical data from a Phase 2 trial
of GVAX(R) vaccine for chronic myelogenous leukemia (CML). Nineteen CML
patients with molecular evidence of persistent leukemia despite more than one
year of Gleevec(R) (imatinib mesylate) therapy were treated with GVAX vaccine
for leukemia while continuing to receive Gleevec. The initial findings of
this trial indicate that the addition of the vaccine to Gleevec therapy has
reduced persistent leukemic disease in 9 of 19 patients to date as
demonstrated by a complete disappearance (five patients) or a greater than one
log (90%) reduction (four patients) in bcr-abl -- a validated genetic marker
found on the leukemic cells. Of the remaining 10 patients, only one patient
has progressed on therapy with GVAX vaccine for leukemia while the other 9
continue to be monitored for reductions in bcr-abl. Reductions of bcr-abl
have been previously shown to be strongly associated with improved
progression-free survival in patients with CML. The trial was conducted at
the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center by Dr. Hyam
Levitsky, professor of Oncology Medicine and Urology, and colleagues, and the
data were presented today at the annual meeting of the American Society of
Hematology (ASH) in Atlanta, GA (ASH Abstract #2858).
The Phase 2 trial enrolled 19 patients with chronic phase CML. All
patients had detectable bcr-abl levels at study entry as measured by a PCR
(polymerase chain reaction) assay despite having received at least one year of
Gleevec therapy. The median duration of Gleevec therapy prior to study entry
was three years. Patients were treated with four injections of GVAX vaccine
for leukemia at three-week intervals over a total treatment period of nine
weeks. Treatment was well tolerated and all patients completed all four
planned treatments. As noted above, to date 9 of the 19 patients have
achieved molecular responses after the four treatments as defined by either a
complete disappearance or greater than one log (90%) reduction in bcr-abl, and
9 of the remaining 10 patients continue to be monitored for reductions in bcr-
abl. In addition, the decline in mean bcr-abl levels from pre- to post-
treatment with GVAX vaccine for leukemia was statistically significant
(p=0.03). Despite the fact that patients were treated with GVAX vaccine for
leukemia for only nine weeks and did not receive booster injections, the
molecular responses are ongoing in seven of nine patients with a median
response duration at this point in the study of greater than five months.
"We are certainly encouraged by the results to date from this Phase 2
trial in CML, in particular by the induction of molecular responses in
patients with persistent leukemic disease despite one or more years of Gleevec
therapy," stated Joseph J. Vallner, Ph.D., president and chief operating
officer of Cell Genesys. "Based on these findings, we plan to continue to
analyze the results from this ongoing trial with the goal of discussing a
potential product registration strategy with the Food and Drug Administration
(FDA)."
The therapy of CML has improved substantially in recent years as a result
of the introduction of Gleevec therapy, which is now approved for the first-
line treatment of CML in chronic phase. Hematologic responses are seen
routinely in the majority of treated patients but complete molecular
responses, as measured by quantitative PCR for bcr-abl, occur in less than 10
percent of patients even after 12 months of therapy. Given that the reduction
in bcr-abl in patients is positively associated with clinical outcome, new
therapeutic strategies to eliminate persistent leukemic disease as evidenced
by bcr-abl positive cells are urgently needed. Moreover, it should be noted
that to date, the only therapeutic intervention shown to be capable of
completely eliminating bcr-abl positive leukemic cells in the majority of
patients is allogeneic bone marrow transplantation, an intensive medical
procedure with significant treatment-related mortality that may not be
indicated in many patients.
Clinical trials of GVAX cancer vaccines are under way for multiple types
of cancer including, in addition to leukemia, prostate cancer and pancreatic
cancer. GVAX vaccines are designed to stimulate an immune response against
the patient's tumor. The vaccines are comprised of tumor cells that have been
genetically modified to secrete GM-CSF, an immune stimulatory hormone that
plays a key role in stimulating the body's immune response to vaccines and are
being developed as non patient-specific "off-the-shelf" pharmaceutical
products. GVAX cancer vaccines have demonstrated a favorable side effect
profile in over 600 patients treated in clinical trials to date.
Cell Genesys is focused on the development and commercialization of novel
biological therapies for patients with cancer. The company is currently
pursuing two clinical stage product platforms -- GVAX(R) cancer vaccines and
oncolytic virus therapies. Ongoing clinical trials include Phase 3 trials of
GVAX vaccine for prostate cancer, Phase 2 trials of GVAX vaccines for leukemia
and pancreatic cancer, and a Phase 1 trial of CG0070 oncolytic virus therapy
for bladder cancer and potentially other types of cancer. Cell Genesys
continues to hold equity interests in its two former subsidiaries -- Abgenix,
Inc., an antibody products company and Ceregene, Inc., which is developing
gene therapies for neurodegenerative disorders. Cell Genesys is headquartered
in South San Francisco, CA and has its principal manufacturing operation in
Hayward, CA. For additional information, please visit the company's website
at http://www.cellgenesys.com.
Statements made herein about the company, other than statements of
historical fact, including statements about the company's progress, results
and timing of clinical trials and pre-clinical programs and the nature of
product pipelines are forward-looking statements and are subject to a number
of uncertainties that could cause actual results to differ materially from the
statements made, including risks associated with the success of clinical
trials and research and development programs, the regulatory approval process
for clinical trials, competitive technologies and products, patents,
continuation of corporate partnerships and the need for additional financings.
For information about these and other risks which may affect Cell Genesys,
please see the company's Annual Report on Form 10-K for the year ended
December 31, 2004 dated March 14, 2005 as well as Cell Genesys' reports on
Form 10-Q and 8-K and other reports filed from time to time with the
Securities and Exchange Commission. The company assumes no obligation to
update the forward-looking information in this press release.
